--- /dev/null
+/*
+ * PCI Backend - Functions for creating a virtual configuration space for
+ * exported PCI Devices.
+ * It's dangerous to allow PCI Driver Domains to change their
+ * device's resources (memory, i/o ports, interrupts). We need to
+ * restrict changes to certain PCI Configuration registers:
+ * BARs, INTERRUPT_PIN, most registers in the header...
+ *
+ * Author: Ryan Wilson <hap9@epoch.ncsc.mil>
+ */
+
+#include <linux/kernel.h>
+#include <linux/pci.h>
+#include "pciback.h"
+#include "conf_space.h"
+#include "conf_space_quirks.h"
+
+#define DEFINE_PCI_CONFIG(op,size,type) \
+int pciback_##op##_config_##size \
+(struct pci_dev *dev, int offset, type value, void *data) \
+{ \
+ return pci_##op##_config_##size (dev, offset, value); \
+}
+
+DEFINE_PCI_CONFIG(read, byte, u8 *)
+DEFINE_PCI_CONFIG(read, word, u16 *)
+DEFINE_PCI_CONFIG(read, dword, u32 *)
+
+DEFINE_PCI_CONFIG(write, byte, u8)
+DEFINE_PCI_CONFIG(write, word, u16)
+DEFINE_PCI_CONFIG(write, dword, u32)
+
+static int conf_space_read(struct pci_dev *dev,
+ struct config_field_entry *entry, int offset,
+ u32 * value)
+{
+ int ret = 0;
+ struct config_field *field = entry->field;
+
+ *value = 0;
+
+ switch (field->size) {
+ case 1:
+ if (field->u.b.read)
+ ret = field->u.b.read(dev, offset, (u8 *) value,
+ entry->data);
+ break;
+ case 2:
+ if (field->u.w.read)
+ ret = field->u.w.read(dev, offset, (u16 *) value,
+ entry->data);
+ break;
+ case 4:
+ if (field->u.dw.read)
+ ret = field->u.dw.read(dev, offset, value, entry->data);
+ break;
+ }
+ return ret;
+}
+
+static int conf_space_write(struct pci_dev *dev,
+ struct config_field_entry *entry, int offset,
+ u32 value)
+{
+ int ret = 0;
+ struct config_field *field = entry->field;
+
+ switch (field->size) {
+ case 1:
+ if (field->u.b.write)
+ ret = field->u.b.write(dev, offset, (u8) value,
+ entry->data);
+ break;
+ case 2:
+ if (field->u.w.write)
+ ret = field->u.w.write(dev, offset, (u16) value,
+ entry->data);
+ break;
+ case 4:
+ if (field->u.dw.write)
+ ret = field->u.dw.write(dev, offset, value,
+ entry->data);
+ break;
+ }
+ return ret;
+}
+
+static inline u32 get_mask(int size)
+{
+ if (size == 1)
+ return 0xff;
+ else if (size == 2)
+ return 0xffff;
+ else
+ return 0xffffffff;
+}
+
+static inline int valid_request(int offset, int size)
+{
+ /* Validate request (no un-aligned requests) */
+ if ((size == 1 || size == 2 || size == 4) && (offset % size) == 0)
+ return 1;
+ return 0;
+}
+
+static inline u32 merge_value(u32 val, u32 new_val, u32 new_val_mask,
+ int offset)
+{
+ if (offset >= 0) {
+ new_val_mask <<= (offset * 8);
+ new_val <<= (offset * 8);
+ } else {
+ new_val_mask >>= (offset * -8);
+ new_val >>= (offset * -8);
+ }
+ val = (val & ~new_val_mask) | (new_val & new_val_mask);
+
+ return val;
+}
+
+static int pcibios_err_to_errno(int err)
+{
+ switch (err) {
+ case PCIBIOS_SUCCESSFUL:
+ return XEN_PCI_ERR_success;
+ case PCIBIOS_DEVICE_NOT_FOUND:
+ return XEN_PCI_ERR_dev_not_found;
+ case PCIBIOS_BAD_REGISTER_NUMBER:
+ return XEN_PCI_ERR_invalid_offset;
+ case PCIBIOS_FUNC_NOT_SUPPORTED:
+ return XEN_PCI_ERR_not_implemented;
+ case PCIBIOS_SET_FAILED:
+ return XEN_PCI_ERR_access_denied;
+ }
+ return err;
+}
+
+int pciback_config_read(struct pci_dev *dev, int offset, int size,
+ u32 * ret_val)
+{
+ int err = 0;
+ struct pciback_dev_data *dev_data = pci_get_drvdata(dev);
+ struct config_field_entry *cfg_entry;
+ struct config_field *field;
+ int req_start, req_end, field_start, field_end;
+ /* if read fails for any reason, return 0 (as if device didn't respond) */
+ u32 value = 0, tmp_val;
+
+ if (unlikely(verbose_request))
+ printk(KERN_DEBUG "pciback: %s: read %d bytes at 0x%x\n",
+ pci_name(dev), size, offset);
+
+ if (!valid_request(offset, size)) {
+ err = XEN_PCI_ERR_invalid_offset;
+ goto out;
+ }
+
+ /* Get the real value first, then modify as appropriate */
+ switch (size) {
+ case 1:
+ err = pci_read_config_byte(dev, offset, (u8 *) & value);
+ break;
+ case 2:
+ err = pci_read_config_word(dev, offset, (u16 *) & value);
+ break;
+ case 4:
+ err = pci_read_config_dword(dev, offset, &value);
+ break;
+ }
+
+ list_for_each_entry(cfg_entry, &dev_data->config_fields, list) {
+ field = cfg_entry->field;
+
+ req_start = offset;
+ req_end = offset + size;
+ field_start = OFFSET(cfg_entry);
+ field_end = OFFSET(cfg_entry) + field->size;
+
+ if ((req_start >= field_start && req_start < field_end)
+ || (req_end > field_start && req_end <= field_end)) {
+ err = conf_space_read(dev, cfg_entry, field_start,
+ &tmp_val);
+ if (err)
+ goto out;
+
+ value = merge_value(value, tmp_val,
+ get_mask(field->size),
+ field_start - req_start);
+ }
+ }
+
+ out:
+ if (unlikely(verbose_request))
+ printk(KERN_DEBUG "pciback: %s: read %d bytes at 0x%x = %x\n",
+ pci_name(dev), size, offset, value);
+
+ *ret_val = value;
+ return pcibios_err_to_errno(err);
+}
+
+int pciback_config_write(struct pci_dev *dev, int offset, int size, u32 value)
+{
+ int err = 0, handled = 0;
+ struct pciback_dev_data *dev_data = pci_get_drvdata(dev);
+ struct config_field_entry *cfg_entry;
+ struct config_field *field;
+ u32 tmp_val;
+ int req_start, req_end, field_start, field_end;
+
+ if (unlikely(verbose_request))
+ printk(KERN_DEBUG
+ "pciback: %s: write request %d bytes at 0x%x = %x\n",
+ pci_name(dev), size, offset, value);
+
+ if (!valid_request(offset, size))
+ return XEN_PCI_ERR_invalid_offset;
+
+ list_for_each_entry(cfg_entry, &dev_data->config_fields, list) {
+ field = cfg_entry->field;
+
+ req_start = offset;
+ req_end = offset + size;
+ field_start = OFFSET(cfg_entry);
+ field_end = OFFSET(cfg_entry) + field->size;
+
+ if ((req_start >= field_start && req_start < field_end)
+ || (req_end > field_start && req_end <= field_end)) {
+ tmp_val = 0;
+
+ err = pciback_config_read(dev, field_start,
+ field->size, &tmp_val);
+ if (err)
+ break;
+
+ tmp_val = merge_value(tmp_val, value, get_mask(size),
+ req_start - field_start);
+
+ err = conf_space_write(dev, cfg_entry, field_start,
+ tmp_val);
+
+ /* handled is set true here, but not every byte
+ * may have been written! Properly detecting if
+ * every byte is handled is unnecessary as the
+ * flag is used to detect devices that need
+ * special helpers to work correctly.
+ */
+ handled = 1;
+ }
+ }
+
+ if (!handled && !err) {
+ /* By default, anything not specificially handled above is
+ * read-only. The permissive flag changes this behavior so
+ * that anything not specifically handled above is writable.
+ * This means that some fields may still be read-only because
+ * they have entries in the config_field list that intercept
+ * the write and do nothing. */
+ if (dev_data->permissive) {
+ switch (size) {
+ case 1:
+ err = pci_write_config_byte(dev, offset,
+ (u8) value);
+ break;
+ case 2:
+ err = pci_write_config_word(dev, offset,
+ (u16) value);
+ break;
+ case 4:
+ err = pci_write_config_dword(dev, offset,
+ (u32) value);
+ break;
+ }
+ } else if (!dev_data->warned_on_write) {
+ dev_data->warned_on_write = 1;
+ dev_warn(&dev->dev, "Driver tried to write to a "
+ "read-only configuration space field at offset "
+ "0x%x, size %d. This may be harmless, but if "
+ "you have problems with your device:\n"
+ "1) see permissive attribute in sysfs\n"
+ "2) report problems to the xen-devel "
+ "mailing list along with details of your "
+ "device obtained from lspci.\n", offset, size);
+ }
+ }
+
+ return pcibios_err_to_errno(err);
+}
+
+void pciback_config_free_dyn_fields(struct pci_dev *dev)
+{
+ struct pciback_dev_data *dev_data = pci_get_drvdata(dev);
+ struct config_field_entry *cfg_entry, *t;
+ struct config_field *field;
+
+ dev_dbg(&dev->dev,
+ "free-ing dynamically allocated virtual configuration space fields\n");
+
+ list_for_each_entry_safe(cfg_entry, t, &dev_data->config_fields, list) {
+ field = cfg_entry->field;
+
+ if (field->clean) {
+ field->clean(field);
+
+ if (cfg_entry->data)
+ kfree(cfg_entry->data);
+
+ list_del(&cfg_entry->list);
+ kfree(cfg_entry);
+ }
+
+ }
+}
+
+void pciback_config_reset_dev(struct pci_dev *dev)
+{
+ struct pciback_dev_data *dev_data = pci_get_drvdata(dev);
+ struct config_field_entry *cfg_entry;
+ struct config_field *field;
+
+ dev_dbg(&dev->dev, "resetting virtual configuration space\n");
+
+ list_for_each_entry(cfg_entry, &dev_data->config_fields, list) {
+ field = cfg_entry->field;
+
+ if (field->reset)
+ field->reset(dev, OFFSET(cfg_entry), cfg_entry->data);
+ }
+}
+
+void pciback_config_free_dev(struct pci_dev *dev)
+{
+ struct pciback_dev_data *dev_data = pci_get_drvdata(dev);
+ struct config_field_entry *cfg_entry, *t;
+ struct config_field *field;
+
+ dev_dbg(&dev->dev, "free-ing virtual configuration space fields\n");
+
+ list_for_each_entry_safe(cfg_entry, t, &dev_data->config_fields, list) {
+ list_del(&cfg_entry->list);
+
+ field = cfg_entry->field;
+
+ if (field->release)
+ field->release(dev, OFFSET(cfg_entry), cfg_entry->data);
+
+ kfree(cfg_entry);
+ }
+}
+
+int pciback_config_add_field_offset(struct pci_dev *dev,
+ struct config_field *field,
+ unsigned int offset)
+{
+ int err = 0;
+ struct pciback_dev_data *dev_data = pci_get_drvdata(dev);
+ struct config_field_entry *cfg_entry;
+ void *tmp;
+
+ /* silently ignore duplicate fields */
+ if (pciback_field_is_dup(dev, field->offset))
+ goto out;
+
+ cfg_entry = kmalloc(sizeof(*cfg_entry), GFP_KERNEL);
+ if (!cfg_entry) {
+ err = -ENOMEM;
+ goto out;
+ }
+
+ cfg_entry->data = NULL;
+ cfg_entry->field = field;
+ cfg_entry->base_offset = offset;
+
+ if (field->init) {
+ tmp = field->init(dev, OFFSET(cfg_entry));
+
+ if (IS_ERR(tmp)) {
+ err = PTR_ERR(tmp);
+ goto out;
+ }
+
+ cfg_entry->data = tmp;
+ }
+
+ dev_dbg(&dev->dev, "added config field at offset 0x%02x\n",
+ OFFSET(cfg_entry));
+ list_add_tail(&cfg_entry->list, &dev_data->config_fields);
+
+ out:
+ if (err)
+ kfree(cfg_entry);
+
+ return err;
+}
+
+/* This sets up the device's virtual configuration space to keep track of
+ * certain registers (like the base address registers (BARs) so that we can
+ * keep the client from manipulating them directly.
+ */
+int pciback_config_init_dev(struct pci_dev *dev)
+{
+ int err = 0;
+ struct pciback_dev_data *dev_data = pci_get_drvdata(dev);
+
+ dev_dbg(&dev->dev, "initializing virtual configuration space\n");
+
+ INIT_LIST_HEAD(&dev_data->config_fields);
+
+ err = pciback_config_header_add_fields(dev);
+ if (err)
+ goto out;
+
+ err = pciback_config_capability_add_fields(dev);
+ if (err)
+ goto out;
+
+ err = pciback_config_quirks_init(dev);
+
+ out:
+ return err;
+}
+
+int pciback_config_init(void)
+{
+ return pciback_config_capability_init();
+}
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